Combustion fasteners offer increased portability over pneumatic fasteners. Combustion fasteners are particularly useful in situations in which the user does not wish to transport a compressor/pneumatic hose for providing compressed air to the pneumatic fastener. For instance, a pneumatic hose may be troublesome in situations in which the pneumatic fastener device or nailer is often repositioned due to the attached pneumatic hose. While combustion fasteners provide portability, the overall dimensions of the combustion device may make utilization awkward due the various components required for operation/the configuration of the device. Additionally, current devices implement combustion events which are ignited at environmental pressure (i.e., standard pressure). Moreover, typical component arrangement may prevent scalability of the design over a range of combustion devices. For example, some typical combustion fastener designs are not suitable, due to their overall size, for implementation with smaller frame fasteners such as brad nailers, finish nailers, or the like due to the size of the included components when compared to a pneumatically operated device. Furthermore, such devices may generate more noise during operation (often due to the inclusion of a reed valve) which may detract from utilization in environment in which small frame fasteners are utilized.
In some instances, even framing combustion fasteners, such as may be utilized when framing a building or for other rough construction, may not be suitable for various tasks. When framing, often the fastening device may have to fit into a limited space such as between two adjoining joists where one of the joists is doubled up with a third joist, for sufficient rigidity and strength, or the like confined area. In other instances, a fastener device may have to be angled to permit toe nailing of a fastener (i.e., drive a nail at an angle other than generally ninety degrees). Typical tasks in-which the size of the device may become an issue include toe nailing rafters and joists, attaching joist hangers, constructing complex roof valley systems, and the like. For instance, typical combustion fasteners require a piston with a large cross-sectional area to generate sufficient kinetic energy to drive a selected fastener. Additionally, typical devices also generate kickback on the handle due to the momentum of the piston.
The size of current combustion fasteners generally may be attributed to need to generate sufficient kinetic energy in a rapid manner to drive the selected fasteners (i.e., nails, staples) as well as the size of a reservoir required for containing fuel. As a result, the piston is usually disposed adjacent the end of the chamber which is opposite the nose (the end of the combustion fastener from which the fasteners are expelled). As the combustion event occurs, the piston is driven toward the nose of the fastener device so as to contact the nail disposed in the path of a blade included in the piston. The piston is then subsequently returned to the end opposite the nose, so the combustion fastener may be reutilized. As a result, the overall dimensions of the combustion fastener may be of a larger size compared to a pneumatically operated device for the same general purpose.
Combustion fastener maintenance may be troublesome as some combustion fasteners may require frequent maintenance (in comparison to a pneumatically operated device) due to fouling, the stresses imposed on various components such as a fan disposed in a combustion chamber. Fouling may require invasive cleaning which necessitates the fastener device be removed from service for an extended amount of time. Inclusion of a fan contained within the chamber in which combustion occurs may necessitate the selection of a device having robust characteristics to ensure proper operation, and sufficient utilization intervals between maintenance, as well as, increasing expense.
Therefore, it would be desirable to provide a combustion fastener constructed to implement two combustion events for providing increased driving capability while decreasing the size of the device over typical devices.